1. Field of the Invention
The present invention relates to a grommet mounted in a through-hole formed on a panel, such as on a vehicle body, such that the grommet is mounted over a wire harness.
2. Description of Related Art
Technology is known for a grommet being mounted over a wire harness, such as that described hereafter.
For example, Japanese Patent Laid-open Publication No. 2008-234904 discloses a grommet including a circular connector around the outer periphery of a central axis in which a wire harness has been inserted. A lip is stretchably joined to the circular connector in an axis-central direction and a flange is joined to the lip.
Japanese Patent Laid-open Publication No. H07-42878 discloses a grommet in which a central portion connects a large diameter portion and a small diameter portion along a central axis, the central portion having a corrugated shape.
However, the grommet disclosed in Japanese Patent Laid-open Publication No. 2008-234904 has a structure in which the through-hole of the body panel is pinched between the lip and the flange. Thus, when the path of the wire harness is skewed, due to a bend developing in the wire harness, for example, while the grommet is attached to the through-hole, portions of the lip in direct contact with the body panel through-hole are likely to deform. Accordingly, there is a risk that adhesion worsens between the lip or the flange and the peripheral edge of the body panel through-hole and that the seal will deteriorate.
The central portion of the grommet disclosed in Japanese Patent Laid-open Publication No. H07-42878 has a shape which is deformable such that an annular portion having a small diameter enters a neighboring annular portion having a large diameter. It is therefore unlikely to bend in a direction orthogonal to the axis direction. Thus, as described above, when the path of the wire harness is skewed, due to a bend developing in the wire harness, for example, force is likely to act on portions of the grommet fixed to the panel. Accordingly, there is a risk that this force will deform the portions of the grommet touching the panel and deteriorate the seal.